Seminars Sorted by Series

Mathematical Conversations

Apr
16
2025

Mathematical Conversations

Visual Aspects of Gaussian Periods
6:00pm|Simons Hall Dilworth Room

Gaussian periods are certain sums of roots of unity.  Gauss introduced them in his work on straight edge and compass constructions of regular polygons.  Since then, Gaussian periods have played important roles in number theory and beyond.  It turns...

Oct
08
2025

Mathematical Conversations

Open Books and Secret Agents
6:00pm|Birch Garden, Simons Hall

An open book is a topological concept aptly named by Elmar Winkelnkemper.

The binding of the book is a fibred knot (of any dimension), and open books and fibred knots are essentially synonymous. Currently the standard reference for the existence and...

Oct
22
2025

Mathematical Conversations

The Chromatic Picture of Stable Homotopy Theory
6:00pm|Birch Garden, Simons Hall

There is a deep connection between stable homotopy theory and the theory of formal groups, first noticed by Quillen. I will describe this connection, and explain how this has led to the chromatic picture of the stable homotopy category.

Nov
05
2025

Mathematical Conversations

Three Fingers are Enough to Count to N (Or, How Not to Hang a Painting)
6:00pm|Simons Hall Dilworth Room

In this talk, I’ll describe one of the most surprising algorithms in computer science: a way to count arbitrarily high while maintaining just three bits of state and a clock. It turns out that the main idea behind the algorithm also appears in a...

Nov
12
2025

Mathematical Conversations

Speaking of Values ...
6:00pm|Simons Hall Dilworth Room

I will talk very briefly about what number theorists call special values of $zeta$ and L-functions. I will start with some familiar, classical equalities and will attempt to touch upon some less familiar (mostly conjectural and very far reaching)...

Dec
03
2025

Mathematical Conversations

Mathematics of the Heart and Spirit: Some Thoughts on Grothendieck
6:00pm|Rubenstein Commons | Meeting Room 5

Alexander Grothendieck was one of the greatest thinkers, and one of the most unusual personalities, in the history of science.  In addition to some biographical details, this talk will offer a perspective on his approach to mathematics.

Dec
10
2025

Mathematical Conversations

Ghosts in My House
6:00pm|Simons Hall Dilworth Room

I will start with an interesting symmetry of plane quadrilaterals and see what mathematics we can reach within 20 minutes.   Also I will explain the title.

Mathematical Physics Seminar

Nov
04
2004

Mathematical Physics Seminar

Conformal Invariance and the Diffusion on Moduli Space for Radial SLE
4:00pm|S-101

We show that a random simple curve in a planar n-connected domain that is conformally invariant and satisfies a Markovian-type property, can be described by a diffusion on a moduli space of dimension 3n-2. Under a natural symmetry condition...

Nov
09
2004

Mathematical Physics Seminar

Matrix Models, Random Partitions, Planar Graphs and Random Surfaces
4:00pm|S-101

"We give an overview of the ideas and techniques relating these seemingly different subjects. I will start from the classical examples, such as enumeration of triangulations by means of one matrix model and counting of colored graphs (Ising model on...

Nov
16
2004

Mathematical Physics Seminar

Seiberg-Witten Theory and Random Partitions
4:00pm|S-101

This will be an overview of the paper hep-th/0306238 written jointly with N. Nekrasov. Our main idea is the interpretation of the low-energy effective prepotential of the N=2 supersymmetric gauge theory as the free energy of a certain natural...

Dec
07
2004

Mathematical Physics Seminar

Large Deviations for a Point Process of Bounded Variability
Eugene Speer
4:00pm|S-101

A (one-dimensional) translation invariant point process of bounded variability is one in which the variance of the number of particles in any interval is bounded, uniformly in the length of the interval. This represents a strong suppression of...

Dec
14
2004

Mathematical Physics Seminar

Jamming and k-core Percolation
Andrea Liu
4:00pm|S-101

We have proposed that the glass transition is one example of a broader class of jamming transitions, where systems can develop extremely long stress relaxation times in disordered states as temperature is lowered, an applied shear stress is lowered...

Jan
23
2006

Mathematical Physics Seminar

Loop-Erased Random Walk
2:00pm|S-101

We will discuss this model of a random simple path and its connection to spanning trees, matrix formulas, the Potts model and SLE. Time permitting, we shall discuss the proof the it has a scaling limit in three dimensions. No prior knowledge will be...

Jan
30
2006

Mathematical Physics Seminar

Matrix Models for Random Circular Ensembles
2:00pm|S-101

We construct an ensemble of (sparse) random matrices whose eigenvalues follow the Gibbs distribution for n particles of Coulomb gas on the unit circle at any given inverse temperature. Our approach combines elements from the theory of orthogonal...

Feb
01
2006

Mathematical Physics Seminar

Universality for Orthogonal and Symplectic Ensembles
Percy Deift
2:00pm|S-101

This is joint work with Dimitri Gioev. The speaker will show how to prove universality in the bulk and at the edge for orthogonal and symplectic ensembles of random matrices with weights of the form exp(-V(x))dx. The method follows the formalism of...

Feb
13
2006

Mathematical Physics Seminar

Lowest Energy States in Non-Relativistic QED
2:00pm|S-101

Within non-relativistic quantum electrodnamics, atoms interacting with the radiation field are expected to have a ground state. It is further expected that the ground state exists independently of the size of the coupling constant $\alpha$ and the...

Feb
20
2006

Mathematical Physics Seminar

Edge and Bulk Currents in 2D Disordered Magnetic Systems
2:00pm|S-101

The integer quantum Hall effect (IQHE) entails a very precise quantization of the Hall conductance in a 2D sample at very low temperatures. Depending on whether the currents in the sample are ascribed to the bulk or the edge, two apparently...

Mar
06
2006

Mathematical Physics Seminar

The Thermodynamics Pressure of a Dilute Fermi Gas
Robert Seiringer
2:00pm|S-101

We consider a gas of fermions with non-zero spin at positive temperature $T$. We show that if the range of the interparticle interaction is small compared to the mean particle distance, the thermodynamic pressure differs to leading order from the...

Apr
10
2006

Mathematical Physics Seminar

On the Fourier Law for Coupled Oscillators
Anti Kupiainen
2:00pm|S-101

We discuss the problem of deriving Fourier's law of heat transport in a Hamiltonian system of coupled anharmonic oscillators subject to boundary noise and derive it in a closure approximation of the stationary state of the system.

Apr
14
2006

Mathematical Physics Seminar

Blow Ups in Complex Solutions of the 3D-Navier-Stokes System and Renormalization Group Method
Yakov Sinai
4:00pm|S-101
Apr
24
2006

Mathematical Physics Seminar

Droplet Minimizers for Free Energy Functionals with a Liquid-Vapor Transition at the Droplet Formation Threshold
Eric Carlen
2:00pm|S-101

We examine several non convex free energy functionals involving a double well potential, and an energy term that penalizes variation in the mass density field. The simplest example is the so--called Cahn--Hilliard functional, which is purely...

May
03
2006

Mathematical Physics Seminar

Directed Polymers with Quenched Randomness: Delocalization Transition and Critical Properties
Fabio Toninelli
2:00pm|S-101

I will present results on the critical behavior of directed polymer models interacting with a defect line, in presence of quenched disorder. These models show a localization-delocalization phase transition. Our main result is that the transition in...

Sep
18
2006

Mathematical Physics Seminar

Cardy's Formula for Certain Models of the Bond-Triangular Type
Lincoln Chayes
4:00pm|S-101

A model based on independent bond percolation is defined. It is demonstrated that this model exhibits critical behavior and, at least at the level of Cardy's formula, has the same limiting continuum behavior as the site model.

Nov
01
2006

Mathematical Physics Seminar

Critical 2d Models on the Annulus
John Cardy
2:30pm|S-101

I conjecture a form for the scaling limit of the partition function of the critical O(n) and Potts models on the annulus, using Coulomb gas methods. This has several subtleties whose elucidation sheds light on the nature of the Coulomb gas mapping.

Nov
10
2006

Mathematical Physics Seminar

Random Band Matrices
4:00pm|S-101

Random band matrices have been proposed as an effective, or toy, model for a disorder induced localization-delocalization transition of eigenstates. Most results about these matrices, and the transition, are based on numerics or on calculations with...

Dec
06
2006

Mathematical Physics Seminar

The Renormalisation Group II
2:30pm|S-101

This is continuation of the previous seminar in which the formulation of the renormalisation group is given in more detail: a space of statistical mechanical models is defined. The renormalisation group is a map on this space and there is a basic...

Feb
07
2007

Mathematical Physics Seminar

Random Conformal Snowflakes
2:30pm|S-101

In this talk we introduce a new class of random fractals which we call conformal snowflakes. We study fine structure of harmonic measure on theses snowflakes. It turns out that in this case the multifractal spectrum of harmonic measure is related to...

Feb
16
2007

Mathematical Physics Seminar

Optimal Transport and Geometric Inequalities
1:30pm|S-101

Since the end of the nineties, the relations of optimal transport with many functional inequalities with geometric content has been revealed and explored by several authors (Barthe, Caffarelli, Cordero, McCann, Otto and others). Sobolev inequalities...

Feb
21
2007

Mathematical Physics Seminar

Full Regularity for the Dissipative Quasi-Geostrophic Equations
2:00pm|S-101

We will present some recent developments in the quasi-geostrophic equations. We show that local solutions to critical and super-critical dissipative quasi-geostrophic equations have higher regularity, although one gets lower derivative in the...

Mar
07
2007

Mathematical Physics Seminar

The Geometry of Grains
4:00pm|S-101

A metal or ceramic is naturally decomposed into cells called "grains". The geometry of this cell complex influences the properties of the material. Some interesting mathematical problems arise in trying to understand the time evolution of these...

Jan
28
2009

Mathematical Physics Seminar

Large Deviations of the Current in Non-Equilibrium Systems
Thierry Bodineau
11:15am|S-101

Using the hydrodynamic limit theory, we will review the large deviations of the heat current through a diffusive system maintained off equilibrium by two heat baths at unequal temperatures. We will also discuss a toy model for dissipative dynamics...

Feb
04
2009

Mathematical Physics Seminar

A Statistical Mechanics Model of Random Matrices
Tom Spencer
11:15am|S-101

Spectral prosperities of random matrices can be described in terms of correlations of a statistical mechanics model with hyperbolic symmetry. This talk will describe and analyze a simpler version of this model which is closely related to random walk...

Feb
13
2009

Mathematical Physics Seminar

New Rigorous Results About the Classical Microcanonical Ensemble
Michael Kiessling
2:00pm|S-101

Rigorous results about the classical microcanonical ensemble have so far been based on the regularization of the microcanonical measure, with the exception of the ideal gas. In this talk I explain that the regularization is not needed for...

Feb
13
2009

Mathematical Physics Seminar

Classical Inequalities for the Boltzmann Collision Operator with Applications to the Inhomogeneous Cauchy Boltzmann Problem
4:00pm|S-101

We study the integrability properties of the gain part of the Boltzmann collision operator using radial symmetrization techniques from harmonic analysis to show Young's inequality for the case of hard potentials and the Hardy-Littlewood-Sobolev...

Feb
20
2009

Mathematical Physics Seminar

Non-Spectral Poles in Asymptotically Hyperbolic Scattering
Robin Graham
4:00pm|S-101

This talk will discuss non-spectral poles of the scattering operator arising in problems with regular singular point behavior at infinity. The phenomenon will be exhibited in a one-dimensional model example involving the Yukawa potential on a half...

Feb
27
2009

Mathematical Physics Seminar

On Lyapunov exponents of Green's function for diffusions and random walks in a random potential
4:00pm|S-101

The talk will consist of two parts. At first, we shall review connections between Lyapunov exponents, large deviations for diffusions in random media, and the homogenization problem for some stochastic Hamilton-Jacobi-Bellman equations. The second...

Mar
04
2009

Mathematical Physics Seminar

Controlled Concentration and Long time Behavior of the Critical Mass Keller-Segel Equation.
Eric Carlen
11:15am|S-101

The Keller-Segal equation exhibits a competition between diffusion and effects leading to concentration, and depending on whether the total mass is above or below a critical value, one or the other wins. We examine the long time behavior for...

Mar
11
2009

Mathematical Physics Seminar

Smoothing Effects for the Full Landau Equation
Robert Strain
11:15am|S-101

The Balescu-Lenard equation from kinetic theory--which was earlier derived in a more complicated form by Bogoliubov--is widely considered to include a highly accurate correction to Landau’s fundamental model for grazing collisions. So far this...

Mar
25
2009

Mathematical Physics Seminar

Infinite/Finite Time Blow-Up for Aggregation Equations in Mathematical Biology
Jose Carrillo
11:15am|S-101

In this talk I will review two recent works in collaboration with A. Bertozzi and T. Laurent and with M. DiFrancesco, A. Figalli, T. Laurent and D. Slepcev in which we prove infinite/finite time blow-up for generic initial data in several models...

Mar
25
2009

Mathematical Physics Seminar

Stability Problems for Crystals, I
Alessio Figalli
2:00pm|S-101

The equilibrium shape of a crystal is determined by the minimization under a volume constraint of its free energy, consisting of an anisotropic interfacial surface energy plus a bulk potential energy. In the absence of the potential term, the...